jmcs / environmental

environmental

Map a python configuration from environment variables.

Overview

environmental allows you to map class properties to environment variables.

By using environmental you can keep your configuration in a single class your IDE understands and have convenient and safe type conversions between the strings stored in your environment and python types.

The created properties are also writable so if you assign to them they will change on your environment and will be available to your child processes.

Installation

$ sudo pip3 install --upgrade environmental

Example

import environmental
import os

class Configuration:
    port = environmental.Int('MY_APPLICATION_HTTP_PORT', 80)
    name = environmental.Str('MY_APPLICATION_NAME', 'Name')

config = Configuration()
config.port = 8080
assert os.environ['MY_APPLICATION_HTTP_PORT'] == '8080'
assert isinstance(os.environ['MY_APPLICATION_HTTP_PORT'], str)
assert config.port == 8080
assert isinstance(config.port, int)

Caveats

Modifying mutable objects in the configuration (like lists) will not work:

import os, environmental
class Configuration:
    list = environmental.List('LIST')

os.environ['LIST'] = "[]"
assert config.list == []
config.list.append('test')
assert config.list == []

But doing something that reassigns the variable will:

config.list += ['test']
assert config.list == ['test']

License

Copyright 2015 Zalando SE

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.